In recent years, the market for a device in which a keyboard and a mouse are not used, such as a smartphone and a tablet type device that includes a slate personal computer (PC) and an iPad (registered trademark), has been rapidly expanding. For example, such an electronic device displays a menu in response to a pressing operation by a user on a touch panel, and then the user selects a menu item from the menu by a following pressing operation with a finger. Upon being pressed in the following pressing operation, the electronic device identifies the selected menu item on the basis of a touch position at which the following pressing operation is performed for the touch panel display.
In addition, there is also an input scheme in which an input pen is used instead of a keyboard and a mouse. For example, in Japanese Laid-open Patent Publication No. 8-95737, a digitizer is disclosed that allows a single menu item to be selected from a plurality of menu items. The digitizer includes an input pen and a coordinate detection unit in which a plurality of loop coils are arrayed. The input pen of the digitizer is used to indicate a position on the basis of electromagnetic coupling to the coordinate detection unit.
The digitizer detects the position touched by the input pen and a tilt direction of the input pen on the basis of detected voltage. When a user tilts the input pen to a certain angle, the tilt direction is determined by detecting sub-peak voltage Vb that appears as a side lobe indicating the tilted direction while a main-peak voltage Va indicating the touched position.
The digitizer selects a main menu item from a plurality of main menu items on the basis of the tilt direction of the input pen. After that, the digitizer selects a sub-menu item from a plurality of sub-menu items that are related to the selected main menu item, on the basis of pressure applied by the input pen.